This type of disc cartridge, as disclosed in, for example, Japanese Patent Laid-Open Publication No. 2000-90626, comprises an upper half and a lower half which rotatably contain an optical disc in between, and a notch is formed in the front surface thereof so that a record and reproduction mechanism having a pickup portion and the like can enter when the disc cartridge is installed in a drive unit, and an opening and a drive opening are formed in the lower surface thereof continuously in a disc radial direction from the notch.
An internal shutter tightly closes the notch in the front surface, and the opening and the drive opening continuing from the notch, when the disc cartridge is not installed in the drive unit. The internal shutter is guided along the upper surface of the lower half.
In the above disc cartridge, since the opening and the drive opening are formed continuously from the front surface in the disc radial direction in a lower shell, stiffness decreases and warpage occurring in molding decreases flatness, so that there are problems that space for rotatably containing the disc does not have enough margin in a thickness direction, and it becomes difficult to smoothly guide the shutter.
Moreover, there is a problem that the above warpage makes dust occurring in the disc cartridge get into the drive unit.
Furthermore, material for an upper shell and the lower shell requires low abrasion, because a gap in a thickness direction between peripheral walls erected upward from the lower shell and erected downward from the upper shell guides the shutter, and the shutter slides along the peripheral walls.
However, it is very difficult that resin material for general purpose use combines low abrasion, high stiffness, and high heat resistance, so that there is a problem that stiffness and heat resistance of the whole disc cartridge cannot be improved without increase in material cost or decrease in moldability.
This invention has been made in view of the above conventional problems, and an object of the present invention is to provide a disc cartridge which has high strength, high moldability, and high resistance to warpage without increase in material cost.
Another object of the present invention is to provide a disc cartridge which improves stiffness and heat resistance on the whole.
The inventor has assiduously pursued his studies, and achieved the above objects by integrally coupling the front surface of the opening to the record and reproduction mechanism in the drive unit without interference to increase the whole stiffness.
In other words, the problems can be solved by the following present invention.
(1) A disc cartridge comprising an upper shell, a center frame, and a lower shell superposed on and coupled to each other in a thickness direction, wherein a disc container space between the upper shell and the center frame rotatably contains a disc recording medium, a center frame opening and a lower shell opening for recording and/or reproducing are formed in the approximately same shape at overlapping positions of the center frame and the lower shell, respectively, to expose a part of a signal recording area of the contained disc recording medium across inner and outer peripheries in a disc radial direction and to the outside of the lower shell in a disc thickness direction, and a reinforcing member is integrally provided in the center frame to couple both sides of the center frame opening in an outer edge of the center frame opening, and in a position separate from a surface of the contained disc recording medium on a lower shell side to an upper shell side in the thickness direction.
(2) The disc cartridge according to (1), wherein the reinforcing member has an L-shaped portion in cross section, the L-shaped portion comprising a peripheral wall erected in the thickness direction of the center frame, and a plane perpendicularly bent from an erected end of the peripheral wall.
(3) The disc cartridge according to (1) or (2), wherein an arc-shaped disc outer peripheral wall is erectly formed in a surface of the center frame on an upper shell side, and the reinforcing member is formed in an arc shape so as to be continued from the disc outer peripheral wall.
(4) The disc cartridge according to (3), wherein a shutter for opening and closing the center frame opening and the lower shell opening is movably contained between the center frame and the lower shell along a plane opposed to the center frame and the lower shell, and the disc outer peripheral wall and the reinforcing member also function as a guide for the shutter.
(5) A disc cartridge comprising an upper shell, a center frame, and a lower shell superposed on and coupled to each other in a thickness direction, wherein a disc container space between the upper shell and the center frame rotatably contains a disc recording medium, a center frame opening and a lower shell opening for recording and/or reproducing are formed in the approximately same shape at overlapping positions of the center frame and the lower shell, respectively, to expose a part of a signal recording area of the contained disc recording medium across inner and outer peripheries in a disc radial direction and to an outside of the lower shell in a disc thickness direction, an arc-shaped disc outer peripheral wall is erectly formed in a surface of the center frame on an upper shell side, and an erected end of the disc outer peripheral wall makes contact with an inner surface of the upper shell to form the disc container space.
(6) A disc cartridge comprising an upper shell, a center frame, and a lower shell superposed on and coupled to each other in a thickness direction, wherein a disc container space between the upper shell and the center frame rotatably contains a disc recording medium, a center frame opening and a lower shell opening for recording and/or reproducing are formed in the approximately same shape at overlapping positions of the center frame and the lower shell, respectively, to expose a part of a signal recording area of the contained disc recording medium across inner and outer peripheries in a disc radial direction and to an outside of the lower shell in a disc thickness direction, an arc-shaped disc outer peripheral wall is erectly formed in a surface of the center frame on an upper shell side, the upper shell and the lower shell are clamped with making contact with each other at a position outside of the disc outer peripheral wall in the thickness direction, and the height of the arc-shaped disc outer peripheral wall is so designed that an end thereof is pressed against an inner surface of the upper shell by clamping force.
(7) A disc cartridge comprising an upper shell, a center frame, and a lower shell superposed on and coupled to each other in a thickness direction, wherein a disc container space between the upper shell and the center frame rotatably contains a disc recording medium, a center frame opening and a lower shell opening for recording and/or reproducing are formed in the approximately same shape at overlapping positions of the center frame and the lower shell, respectively, to expose a part of a signal recording area of the contained disc recording medium across inner and outer peripheries in a disc radial direction and to an outside of the lower shell in a disc thickness direction, a width of the center frame opening in a disc rotational direction is larger than that of the lower shell opening, and both ends of the center frame opening in a width direction are disposed outside of both ends of the lower shell opening in the width direction.
(8) A disc cartridge comprising an upper shell, a center frame, and a lower shell superposed on and coupled to each other in a thickness direction, wherein a disc container space between the upper shell and the center frame rotatably contains a disc recording medium, a center frame opening and a lower shell opening for recording and/or reproducing are formed in the approximately same shape at overlapping positions of the center frame and the lower shell, respectively, to expose a part of a signal recording area of the contained disc recording medium across inner and outer peripheries in a disc radial direction and to an outside of the lower shell in a disc thickness direction, at least an inner surface of the lower shell is made of material with low slide frictional resistance, and the upper shell is made of material having higher heat resistance and stiffness than material for the inner surface of the lower shell.
(9) The disc cartridge according to (5) or (6), wherein a reinforcing member is integrally provided in the center frame to couple both sides of the center frame opening in an outer edge of the center frame opening, and in a position separate from a surface of the contained disc recording medium on a lower shell side to an upper shell side in the thickness direction, and the reinforcing member is formed in an arc shape so as to be continued to the disc outer peripheral wall.
(10) The disc cartridge according to (7) or (8), wherein a reinforcing member is integrally provided in the center frame to couple both sides of the center frame opening in an outer edge of the center frame opening, and in a position separate from a surface of the contained disc recording medium on a lower shell side to an upper shell side in the thickness direction.
(11) The disc cartridge according to (10), wherein an arc-shaped disc outer peripheral wall is erectly formed in the surface of the center frame on an upper shell side, and an erected end of the disc outer peripheral wall makes contact with an inner surface of the upper shell to form the disc container space, and the reinforcing member is formed in an arc shape so as to be continued from the disc outer peripheral wall.
(12) The disc cartridge according to any of (1), (4), (9), (10) and (11), wherein a lower shell reinforcing member is integrally provided in an inner surface of the lower shell to integrally continue both ends of the lower shell opening, in such a manner as to be adjacent in parallel to the reinforcing member in a disc radial direction and be superposed on the reinforcing member in a disc thickness direction.